// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_GFX_ICON_UTIL_H_
#define UI_GFX_ICON_UTIL_H_

#include <stddef.h>
#include <stdint.h>
#include <string>
#include <vector>
#include <windows.h>

#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "base/win/scoped_gdi_object.h"
#include "ui/gfx/geometry/point.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/gfx_export.h"

namespace base {
class FilePath;
}

namespace gfx {
class ImageFamily;
class Size;
}
class SkBitmap;

///////////////////////////////////////////////////////////////////////////////
//
// The IconUtil class contains helper functions for manipulating Windows icons.
// The class interface contains methods for converting an HICON handle into an
// SkBitmap object and vice versa. The class can also create a .ico file given
// a PNG image contained in an SkBitmap object. The following code snippet
// shows an example usage of IconUtil::CreateHICONFromSkBitmap():
//
//   SkBitmap bitmap;
//
//   // Fill |bitmap| with valid data
//   bitmap.setConfig(...);
//   bitmap.allocPixels();
//
//   ...
//
//   // Convert the bitmap into a Windows HICON
//   base::win::ScopedHICON icon(IconUtil::CreateHICONFromSkBitmap(bitmap));
//   if (!icon.is_valid()) {
//     // Handle error
//     ...
//   }
//
//   // Use the icon with a WM_SETICON message
//   ::SendMessage(hwnd, WM_SETICON, static_cast<WPARAM>(ICON_BIG),
//                 reinterpret_cast<LPARAM>(icon.get()));
//
///////////////////////////////////////////////////////////////////////////////
class GFX_EXPORT IconUtil {
public:
    // ATOMIC_WRITE ensures that a partially written icon won't be created even if
    // Chrome crashes part way through, but ATOMIC_WRITE is more expensive than
    // NORMAL_WRITE. See CreateIconFileFromImageFamily. ATOMIC_WRITE is the
    // default for historical reasons.
    enum WriteType { ATOMIC_WRITE,
        NORMAL_WRITE };
    // The size of the large icon entries in .ico files on Windows Vista+.
    enum { kLargeIconSize = 256 };
    // The size of icons in the medium icons view on Windows Vista+. This is the
    // maximum size Windows will display an icon that does not have a 256x256
    // image, even at the large or extra large icons views.
    enum { kMediumIconSize = 48 };

    // The dimensions for icon images in Windows icon files. All sizes are square;
    // that is, the value 48 means a 48x48 pixel image. Sizes are listed in
    // ascending order.
    static const int kIconDimensions[];

    // The number of elements in kIconDimensions.
    static const size_t kNumIconDimensions;
    // The number of elements in kIconDimensions <= kMediumIconSize.
    static const size_t kNumIconDimensionsUpToMediumSize;

    // Given an SkBitmap object, the function converts the bitmap to a Windows
    // icon and returns the corresponding HICON handle. If the function cannot
    // convert the bitmap, NULL is returned.
    //
    // The client is responsible for destroying the icon when it is no longer
    // needed by calling ::DestroyIcon().
    static base::win::ScopedHICON CreateHICONFromSkBitmap(const SkBitmap& bitmap);

    // Given a valid HICON handle representing an icon, this function converts
    // the icon into an SkBitmap object containing an ARGB bitmap using the
    // dimensions specified in |s|. |s| must specify valid dimensions (both
    // width() an height() must be greater than zero). If the function cannot
    // convert the icon to a bitmap (most probably due to an invalid parameter),
    // the return value is NULL.
    //
    // The client owns the returned bitmap object and is responsible for deleting
    // it when it is no longer needed.
    static SkBitmap* CreateSkBitmapFromHICON(HICON icon, const gfx::Size& s);

    // Loads an icon resource  as a SkBitmap for the specified |size| from a
    // loaded .dll or .exe |module|. Supports loading smaller icon sizes as well
    // as the Vista+ 256x256 PNG icon size. If the icon could not be loaded or
    // found, returns a NULL scoped_ptr.
    static scoped_ptr<gfx::ImageFamily> CreateImageFamilyFromIconResource(
        HMODULE module,
        int resource_id);

    // Given a valid HICON handle representing an icon, this function converts
    // the icon into an SkBitmap object containing an ARGB bitmap using the
    // dimensions of HICON. If the function cannot convert the icon to a bitmap
    // (most probably due to an invalid parameter), the return value is NULL.
    //
    // The client owns the returned bitmap object and is responsible for deleting
    // it when it is no longer needed.
    static SkBitmap* CreateSkBitmapFromHICON(HICON icon);

    // Creates Windows .ico file at |icon_path|. The icon file is created with
    // multiple BMP representations at varying predefined dimensions (by resizing
    // an appropriately sized image from |image_family|) because Windows uses
    // different image sizes when loading icons, depending on where the icon is
    // drawn (ALT+TAB window, desktop shortcut, Quick Launch, etc.).
    //
    // If |image_family| contains an image larger than 48x48, the resulting icon
    // will contain all sizes up to 256x256. The 256x256 image will be stored in
    // PNG format inside the .ico file. If not, the resulting icon will contain
    // all sizes up to 48x48.
    //
    // The function returns true on success and false otherwise. Returns false if
    // |image_family| is empty.
    static bool CreateIconFileFromImageFamily(
        const gfx::ImageFamily& image_family,
        const base::FilePath& icon_path,
        WriteType write_type = ATOMIC_WRITE);

    // Creates a cursor of the specified size from the DIB passed in.
    // Returns the cursor on success or NULL on failure.
    static base::win::ScopedHICON CreateCursorFromDIB(const gfx::Size& icon_size,
        const gfx::Point& hotspot,
        const void* dib_bits,
        size_t dib_size);

private:
    // The icon format is published in the MSDN but there is no definition of
    // the icon file structures in any of the Windows header files so we need to
    // define these structure within the class. We must make sure we use 2 byte
    // packing so that the structures are laid out properly within the file.
    // See: http://msdn.microsoft.com/en-us/library/ms997538.aspx
#pragma pack(push)
#pragma pack(2)

    // ICONDIRENTRY contains meta data for an individual icon image within a
    // .ico file.
    struct ICONDIRENTRY {
        BYTE bWidth;
        BYTE bHeight;
        BYTE bColorCount;
        BYTE bReserved;
        WORD wPlanes;
        WORD wBitCount;
        DWORD dwBytesInRes;
        DWORD dwImageOffset;
    };

    // ICONDIR Contains information about all the icon images contained within a
    // single .ico file.
    struct ICONDIR {
        WORD idReserved;
        WORD idType;
        WORD idCount;
        ICONDIRENTRY idEntries[1];
    };

    // GRPICONDIRENTRY contains meta data for an individual icon image within a
    // RT_GROUP_ICON resource in an .exe or .dll.
    struct GRPICONDIRENTRY {
        BYTE bWidth;
        BYTE bHeight;
        BYTE bColorCount;
        BYTE bReserved;
        WORD wPlanes;
        WORD wBitCount;
        DWORD dwBytesInRes;
        WORD nID;
    };

    // GRPICONDIR Contains information about all the icon images contained within
    // a RT_GROUP_ICON resource in an .exe or .dll.
    struct GRPICONDIR {
        WORD idReserved;
        WORD idType;
        WORD idCount;
        GRPICONDIRENTRY idEntries[1];
    };

    // Contains the actual icon image.
    struct ICONIMAGE {
        BITMAPINFOHEADER icHeader;
        RGBQUAD icColors[1];
        BYTE icXOR[1];
        BYTE icAND[1];
    };
#pragma pack(pop)

    friend class IconUtilTest;

    // Returns true if any pixel in the given pixels buffer has an non-zero alpha.
    static bool PixelsHaveAlpha(const uint32_t* pixels, size_t num_pixels);

    // A helper function that initializes a BITMAPV5HEADER structure with a set
    // of values.
    static void InitializeBitmapHeader(BITMAPV5HEADER* header, int width,
        int height);

    // Given a single SkBitmap object and pointers to the corresponding icon
    // structures within the icon data buffer, this function sets the image
    // information (dimensions, color depth, etc.) in the icon structures and
    // also copies the underlying icon image into the appropriate location.
    // The width and height of |bitmap| must be < 256.
    // (Note that the 256x256 icon is treated specially, as a PNG, and should not
    // use this method.)
    //
    // The function will set the data pointed to by |image_byte_count| with the
    // number of image bytes written to the buffer. Note that the number of bytes
    // includes only the image data written into the memory pointed to by
    // |icon_image|.
    static void SetSingleIconImageInformation(const SkBitmap& bitmap,
        size_t index,
        ICONDIR* icon_dir,
        ICONIMAGE* icon_image,
        size_t image_offset,
        size_t* image_byte_count);

    // Copies the bits of an SkBitmap object into a buffer holding the bits of
    // the corresponding image for an icon within the .ico file.
    static void CopySkBitmapBitsIntoIconBuffer(const SkBitmap& bitmap,
        unsigned char* buffer,
        size_t buffer_size);

    // Given a set of bitmaps with varying dimensions, this function computes
    // the amount of memory needed in order to store the bitmaps as image icons
    // in a .ico file.
    static size_t ComputeIconFileBufferSize(const std::vector<SkBitmap>& set);

    // A helper function for computing various size components of a given bitmap.
    // The different sizes can be used within the various .ico file structures.
    //
    // |xor_mask_size| - the size, in bytes, of the XOR mask in the ICONIMAGE
    //                   structure.
    // |and_mask_size| - the size, in bytes, of the AND mask in the ICONIMAGE
    //                   structure.
    // |bytes_in_resource| - the total number of bytes set in the ICONIMAGE
    //                       structure. This value is equal to the sum of the
    //                       bytes in the AND mask and the XOR mask plus the size
    //                       of the BITMAPINFOHEADER structure. Note that since
    //                       only 32bpp are handled by the IconUtil class, the
    //                       icColors field in the ICONIMAGE structure is ignored
    //                       and is not accounted for when computing the
    //                       different size components.
    static void ComputeBitmapSizeComponents(const SkBitmap& bitmap,
        size_t* xor_mask_size,
        size_t* bytes_in_resource);

    // A helper function of CreateSkBitmapFromHICON.
    static SkBitmap CreateSkBitmapFromHICONHelper(HICON icon,
        const gfx::Size& s);

    // Prevent clients from instantiating objects of that class by declaring the
    // ctor/dtor as private.
    DISALLOW_IMPLICIT_CONSTRUCTORS(IconUtil);
};

#endif // UI_GFX_ICON_UTIL_H_
